Shaft seal assembly

Abstract

An illustrative embodiment of a shaft seal assembly generally includes a fixed stator, a floating stator, and a sealing member. In the illustrative embodiment the fixed stator may be formed with one or more fluid conduits that are in fluid communication with one or fluid conduits formed in the floating stator. The fluid conduits in the floating stator may be in fluid communication with one or more fluid conduits formed in a sealing member. A rotational interface may exist between the sealing member and a shaft, and the various fluid conduits may be configured to create a fluid barrier at that interface. Other embodiments of a shaft seal assembly may create a fluid barrier at a rotational interface between a rotor and a floating stator.

What is claimed is: 
     
       1. A shaft seal assembly, comprising:
 a stator assembly comprising: 
 a first stator; and 
 a second stator coupled within the first stator and configured to move with respect to the first stator; 
 a sealing member coupled within the second stator and configured to move with respect to the second stator and to receive a shaft; 
 one or more seals between the first stator and the second stator; and 
 
       one or more seals between the second stator and the sealing member,
 wherein: 
 the sealing member is configured to move in a radial direction with respect to at least one of the stators and to articulate with respect to at least one of the stators, 
 the sealing member comprises: 
 a radial interior surface that forms a rotational interface with the shaft; 
 a radial exterior surface that forms an interface with the second stator; 
 a recess extending from the radial exterior surface partially into the sealing member without extending through the radial interior surface, the recess being configured to receive at least a portion of a pin secured to the second stator; and 
 two or more sets of cylindrical radial bores extending through the sealing member and intersecting the radial interior surface to form cylindrical bore openings on the radial interior surface and intersecting the radial exterior surface to form cylindrical bore openings on the radial exterior surface, the recess being located between a cylindrical radial bore of a first set of cylindrical radial bores and a cylindrical radial bore of a second set of cylindrical radial bores, each of the cylindrical radial bores in the first set of cylindrical radial bores being aligned with a corresponding cylindrical radial bore in the second set of cylindrical radial bores, and 
 the first stator comprises one or more passages configured to receive sealing fluid and to pass the sealing fluid to an outer surface of the second stator, 
 the second stator comprises one or more passages configured to pass the sealing fluid from the outer surface of the second stator to the radial exterior surface of the sealing member, the first stator, second stator, and the one or more seals between the first stator and the second stator are configured such that a majority of the sealing fluid passes through the one or more passages in the second stator, and 
 the second stator, the sealing member and the one or more seals between the second stator and the sealing member are configured such that a majority of the sealing fluid exiting the second stator passes through the two or more sets of cylindrical radial bores and exits the cylindrical radial bores at the cylindrical bore openings on the radial interior surface such that the radial interior surface creates a pressurized fluid barrier between the shaft and the sealing member at the radial interior surface. 
 
     
     
       2. The shaft seal assembly of  claim 1 , wherein the radial exterior surface of the sealing member comprises a convex surface configured to form the interface as a spherical interface. 
     
     
       3. The shaft seal assembly of  claim 1 , further comprising a face plate configured to inhibit axial movement of at least one of the stators. 
     
     
       4. The shaft seal assembly of  claim 1 , wherein the two or more sets of cylindrical radial bores comprise a pair of opposing sets of cylindrical radial bores along the axis of the sealing member. 
     
     
       5. The shaft seal assembly of  claim 1 , wherein the cylindrical radial bores of at least one set of cylindrical radial bores are evenly spaced about the periphery of the sealing member. 
     
     
       6. The shaft seal assembly of  claim 1 , wherein:
 the radial exterior surface of the sealing member comprises a convex surface configured to form the interface as a spherical interface, 
 
       each of the first set of cylindrical radial bores and the second set of cylindrical radial bores includes a corresponding set of fluid inlets intersecting the convex surface of the sealing member,
 the first set of cylindrical radial bores is axially spaced in a first direction from the one or more passages of the second stator, and 
 
       the second set of cylindrical radial bores is axially spaced in a second direction from the one or more passages of the second stator that is opposite the first direction. 
     
     
       7. The shaft seal assembly of  claim 1 , wherein each of the first set of cylindrical radial bores and the second set of cylindrical radial bores includes a corresponding set of fluid inlets intersecting the convex surface of the sealing member.